1. Field of the Invention
The present invention relates to an image processing apparatus, an image processing method, and a program for performing a predetermined process on an inputted image.
2. Description of the Related Art
Conventionally, an image capturing method is known in which a main object is focused and the background is blurred when capturing an image by a digital camera. In such an image capturing method, a point light source is blurred, so that a ball blur is generated at a portion corresponding to the point light source and an image with a fantastic effect can be obtained. Such a ball blur is generated by the optical characteristics of a lens of the digital camera and the brightness varies in a ball-shaped blurring image. The point light source is an area having a certain size at which local light is present. Bokeh is a term of art commonly used to describe the aesthetic quality of a blur in out of focus areas of images.
A method is known in which image data is obtained and the image data is processed into an image where a ball blur is generated by image processing (see Japanese Patent Laid-Open No. 2009-003858 and Japanese Patent Laid-Open No. 2009-218704).
Japanese Patent Laid-Open No. 2009-003858 discloses a method for changing the size or the shape of a light source area when blurring the light source area by selecting one of a plurality of filters prepared in advance for the light source area in an image. Japanese Patent Laid-Open No. 2009-218704 discloses a method for performing image enhancement processing on a high luminance portion when performing a background blurring process.
A ball blur portion in an image actually captured by a digital camera varies in a complicated manner by the optical characteristics of a lens. Therefore, it is not possible for the methods disclosed by the Japanese Patent Laid-Open No. 2009-003858 and Japanese Patent Laid-Open No. 2009-218704 to reproduce the feeling of an image obtained by actual image capturing.